The present invention relates to a device for rotational locking of a fastening element. More particularly, the present invention relates to a device which functions as a lock or a shoulder for fastening elements, such as bolts or screws which are arranged in cast or forged materials. Still more particularly, the present invention relates to a method for producing such a device.
Construction elements such as forged beams and attachment consoles in, for example, motor vehicles often comprise through holes for bolts and similar fastening elements. These fastening elements can be used to attach various components to the beam or the attachment console.
In connection with heavy cargo vehicles, for example, such attachment consoles are often utilized for attaching heavy components, such as for attaching the front axle of the vehicle. For this purpose the attachment console can be made from a cast or forged material, for example nodular iron.
FIG. 1 shows a top view of a section of a previously known construction element in the shape of an attachment console 1, which according to conventional technology is shaped by casting. The attachment console 1 comprises a recess 2, which has been shaped during the casting process. At the bottom of the recess 2, there is a through hole 3. The arrangement is also explained by FIG. 2, which shows a cross-sectional view of the attachment console 1. The hole 3 is intended for an attachment element in the form of a bolt 4. The inner side walls of the recess 2 are dimensioned with somewhat larger inner dimensions than the outer dimensions of the head 5 of the bolt 4. In this way, these side walls can serve as a lock or a shoulder for the bolt 4, so that it will not rotate when it is attached by means of a nut 6 or a similar component at the rear side of the attachment console 1.
Although the above-mentioned arrangement functions relatively satisfactorily for locking the bolt 4, it has a serious drawback in that the hole 3 in the recess 2 must be positioned and drilled with a very high degree of accuracy. If the position of the hole 3 deviates too much sideways from the line of symmetry in the bottom surface of the recess 2, the head 5 of the bolt 4 cannot be housed in the recess 2, i.e. it will simply not be possible to bring the bolt 4 down into the hole 3. This, in turn, means that very high demands must be made on the manufacturing and processing of the attachment console 1, where in particular very high tolerances are demanded when drilling the hole 3. This of course leads to time- and cost-consuming measures, which are not desirable.
The object of the present invention is to obtain an improved device for rotational locking of a fastening element, such as a screw, a bolt or a nut in a construction element, which device both provides for secure locking of the fastening element and permits a relatively high tolerance when drilling said hole.
A further object of the present invention is to provide a process for manufacturing the above-mentioned arrangement.
In accordance with the present invention, these and other objects have now been realized by the invention of a device for locking a rotatable fastening element in a construction element comprising a shaped surface disposed in the construction element, the shaped surface defining an axis of rotation for the rotatable fastening element, and a locking member for the rotatable fastening element comprising at least one protrusion extending into the shaped surface, whereby the at least one protrusion may be processed with respect to the axis of rotation of the rotatable fastening element to create an end surface on the at least one protrusion which is a predetermined distance from the axis of rotation of the rotatable fastening element irrrespective of the location of the axis of rotation relative to the shaped surface. In a preferred embodiment, the shaped surface includes a through hole extending through the construction element, the through hole corresponding to the axis of rotation of the rotatable fastening element.
In accordance with one embodiment of the device of the present invention, the shaped surface comprises a recessed portion of the construction element. In a preferred embodiment, the at least one protrusion comprises a plurality of protrusions, whereby the axial surfaces of each of the plurality of protrusions is located the predetermined distance from the axis of rotation of the rotatable fastening element. In a more preferred embodiment, the recessed portion includes an inner wall, and each of the plurality of protrusions extends from the inner wall towards the axis of rotation of the rotatable fastening element. Preferably, each of the plurality of protrusions is disposed an equal distance from every other of the plurality of protrusions.
In accordance with another embodiment of the device of the present invention, the construction element is cast, forged and sintered material. In another embodiment, the construction element is a console of a motor vehicle.
In accordance with the method of the present invention, a method has been provided for producing a device for locking a rotatable fastening element in a construction element, the method comprising forming a shaped surface in the construction element, the shaped surface including an axis of rotation for the rotatable fastening element, forming at least one protrusion from the shaped surface of the construction element towards the axis of rotation of the rotatable fastening element, and processing the at least one protrusion to provide an end surface on the at least one protrusion a predetermined distance from the axis of rotation of the rotatable fastening element irrespective of the location of the axis of rotation with respect to the shaped surface. In a preferred embodiment, the method includes providing a through hole in the construction element at a location in the shaped surface corresponding to the axis of rotation of the rotatable fastening element.
In accordance with one embodiment of the method of the present invention, the shaped surface comprises a recessed portion of the construction element.
In accordance with another embodiment of the method of the present invention, the forming of the at least one protrusion comprises forming a plurality of the protrusions, and the processing step comprises processing the plurality of protrusions whereby the end surfaces of each of the plurality of protrusions is the predetermined distance from the axis of rotation of the rotatable fastening element. In a preferred embodiment, forming of the shaped surface comprises casting or forging. In another embodiment, forming of the at least one protrusion comprises casting or forging.
In accordance with another embodiment of the method of the present invention, processing of the plurality of protrusions comprises milling.
The present invention thus provides a device for locking, in the direction of rotation, a rotatable fastening element in a construction element, e.g. a fastening console. The present invention comprises a recessed part formed in the construction element, in which recessed part a hole is made, and where the recessed part also comprises means for locking of the fastening element. According to the present invention, that means comprise at least one protruding element which has been formed in the bottom surface of the recessed part, which protruding element is shaped with an edge surface which faces the hole and which has been positioned at a predetermined distance from the center of the hole.
Since the hole can now be drilled with a low degree of accuracy, a construction element can now be produced at a low cost.
The term xe2x80x9cfastening elementxe2x80x9d in this context refers to screws, bolts and similar components which are intended for rotatable or screwable positioning through a hole in a construction element, e.g. a fastening console. This term also refers to nuts and similar components which are intended to interact with screws or similar components.